The present invention aims to provide a porous separation membrane that does not suffer a significant decrease in the protein permeability even after long term use. The porous separation membrane has an asymmetric structure with a dense layer forming one surface layer and with a coarse layer forming the other surface layer, supports a biocompatible polymer, and meet the requirements (1) and (2) given below in surface analysis of a cross section containing the dense layer and the coarse layer performed by TOF-SIMS: (1) the minimum value of normalized intensity of the ion signal attributed to the biocompatible polymer in the coarse layer is 0.15 times or more of the maximum value, and (2) the normalized average intensity of the ion signal attributed to the biocompatible polymer in the dense layer is 2.0 times or more of the normalized average intensity of the ion signal attributed to carboxylic acid in the coarse layer.

A virus removal membrane includes cellulose, and a primary-side surface through which the protein-containing solution is to be applied and a secondary-side surface from which a permeate that has permeated the virus removal membrane is to be flowed, wherein a bubble point is 0.5 MPa or more and 1.0 MPa or less; and when a solution containing gold colloids having a diameter of 30 nm is applied through the primary-side surface to the virus removal membrane to allow the virus removal membrane to capture the gold colloids for measurement of brightness in a cross section of the virus removal membrane, a value obtained by dividing a standard deviation of a value of an area of a spectrum of variation in the brightness by an average of the value of the area of the spectrum of variation in the brightness is 0.01 or more and 0.30 or less.

The present disclosure provides a gas separation membrane module that has high, long-term utility. The present disclosure provides a gas separation membrane module that has: a housing; a gas separation membrane that is arranged inside the housing; and an adhesive part that fixes the gas separation membrane to the housing.

The present disclosure relates to hollow fiber tangential flow filter units, including hollow fiber tangential flow depth filter units, for various applications, including bioprocessing and pharmaceutical applications, systems employing such filters, and methods of filtration using the same.

A method for forming an isoporous graded film comprising multiblock copolymers and isoporous graded films. The films have a surface layer and a bulk layer. The surface layer can have at least 1×10.sup.14 pores/m.sup.2 and a pore size distribution (d.sub.max/d.sub.min)) of less than 3. The bulk layer has an asymmetric structure. The films can be used in filtration applications.

The present disclosure discloses an asymmetric electrolyte membrane, a membrane electrode assembly including the same, a water electrolysis apparatus including the same and a method for manufacturing the same. More particularly, it discloses an asymmetric electrolyte membrane having a porous layer and a dense layer at the same time, a membrane electrode assembly including the same, a water electrolysis apparatus including the same and a method for manufacturing the same.

A process for preparing a base oil fraction having a reduced cloud point from a hydrocarbon feed which is derived from a Fischer-Tropsch process is provided. The process comprises: subjecting a hydrocarbon feed which is derived from a Fischer-Tropsch process to a catalytic dewaxing treatment to obtain an at least partially isomerised product; separating at least part of the at least partially isomerised product into one or more light hydrocarbon fractions and one or more heavy base oil fractions; separating at least one of the heavy base oil fractions by means of a first membrane into a first permeate and a first retentate; separating at least part of the first permeate by means of a second membrane into a second permeate and a second retentate; and recovering the second permeate.

An object of the present invention is to provide a hollow fiber membrane with enhanced phosphorus-removing performance without impairing antithrombogenicity in order to inhibit in vivo accumulation of phosphate ions in living body that might cause bone metabolism disorders. The present inventors have found that a hollow fiber membrane having a specific membrane structure and a specific membrane composition possesses a very useful range for inner surface charges of the membrane. More particularly, the inventors have discovered that the above object can be achieved in a limited range in which the zeta potential on the inner surface of a hollow fiber membrane measured under given certain conditions is greater than −3.0 mV but less than 0 mV. This finding has led to the completion of the present invention.

The present invention provides a porous hollow fiber membrane including a polysulfone-based polymer and a hydrophilic polymer, and having a dense layer in a section from an outer surface portion to a center region of a membrane thickness, a thickness of the dense layer being 10 to 30 μm, and a ratio of a pore having a pore size of more than 50 nm and a ratio of a pore having a pore size of 10 nm or smaller in the dense layer being 25 to 40% and 20% or less, respectively.

Hydrophilic flat-sheet membrane based on a hydrophobic first polymer from the group consisting of aromatic sulfone polymers and a hydrophilic second polymer, wherein the membrane has a thickness in the range between 30 and 200 μm, a first and a second surface and a supporting layer having a three-dimensional sponge-like network structure, wherein the supporting layer has a first cover layer on the side thereof facing the first surface and a second cover layer on the side thereof facing the second surface, which cover layers are formed integrally with the supporting layer, and wherein the first and second surfaces have approximately oval or circular openings which penetrate the first and second cover layers, respectively, and are connected to the supporting layer, wherein the average diameter of the openings in the surfaces differ by a factor of less than 2, wherein the three-dimensional network structure of the supporting layer is made up of thick branches and a continuous pore system, and the predominant proportion of the branches have a diameter of at least 0.5 μm at the thinnest point thereof and wherein the pores in the supporting layer are larger than the openings in the surfaces.